Clear understanding of the links between ecological functions and biodiversity is needed to asses... more Clear understanding of the links between ecological functions and biodiversity is needed to assess and predict the true environmental consequences of human activities. Several key ecosystem functions are provided by coprophagous beetles in the subfamily Scarabaeinae (Coleoptera: Scarabaeidae), which feed on animal excreta as both adults and larvae. Through manipulating feces during the feeding process, dung beetles instigate a series of ecosystem functions ranging from secondary seed dispersal to nutrient cycling and parasite suppression. Many of these ecological functions provide valuable ecosystem services such as biological pest control and soil fertilization. Here we summarize the contributions of dung beetles to nutrient cycling, bioturbation, plant growth enhancement, secondary seed dispersal and parasite control, as well as highlight their more limited role in pollination and trophic regulation. We discuss where these ecosystem functions clearly translate into ecosystem services, outline areas in critical need of additional research and describe a research agenda to fill those gaps. Due to the high sensitivity of dung beetles to habitat modification and changing dung resources, many of these ecological processes have already been disrupted or may be affected in the future. Prediction of the functional consequences of dung beetle decline demands functional studies conducted with naturally assembled beetle communities, which broaden the geographic scope of existing work, assess the spatio-temporal distribution of multiple functions, and link these ecosystem processes more clearly to ecosystem services.
Experimental studies linking community composition to functioning are typically confined to small... more Experimental studies linking community composition to functioning are typically confined to small and closed micro- or mesocosms. Such restricted conditions may affect both species’ biology and their environment. Yet, targeting simple features in the behaviour of species may circumvent these constraints. Focusing on ecological functions provided by dung beetles, we test whether large, open-top cages – MESOCLOSURES – will intercept the flight trajectories of beetles, thereby allowing manipulation of local community composition.MESOCLOSURES were built in both tropical forest (Brazil) and temperate grasslands (Finland), thus testing their general efficiency. Within the respective environments, we varied different aspects of MESOCLOSURE design: in the tropical forest, we examined the impact of MESOCLOSURE dimensions on exclusion efficiency, whereas in the temperate grassland, we assessed the potential for selectively excluding and including community members by different mesh sizes. In the temperate environment, we also went from method to application, using MESOCLOSURES to relate community composition to functioning under two simulated grazing regimes.MESOCLOSURES allowed efficient manipulation of dung beetle communities, maintaining dung beetle densities at intended levels in both temperate and tropical systems. In the tropics, the smallest cages (1 × 1 m) offered the highest contrast in beetle densities inside vs. outside of the fence, whereas the largest cages (9 × 9 m) offered the lowest. Nonetheless, densities inside cages never exceed one-fifth of those outside. At the temperate site, manipulations of community structure through mesh size yielded significant differences in functioning and suggested an interaction between small dung-dwelling species and large tunnelling species. Within cages, higher grazing was reflected in augmented dung removal.We conclude that MESOCLOSURES can be effectively used to study dung beetle functions across habitats and latitudes. As applied insights, the present study adds resolution to the significance of different functional groups of dung beetles and shows that grazing pressure may have an important impact on the ecosystem functions that they provide. Overall, this study suggests that targeted manipulation of dispersal may offer new solutions for linking fauna to ecosystem functions with minimal impact on the processes measured.
Brazilian journal of biology = Revista brasleira de biologia, 2010
The objectives of this study were to evaluate the influence of propagules source and the implicat... more The objectives of this study were to evaluate the influence of propagules source and the implication of tree size class on the spatial pattern of Xylopia brasiliensis Spreng. individuals growing under the canopy of an experimental plantation of eucalyptus. To this end, all individuals of Xylopia brasiliensis with diameter at soil height (dsh) > 1 cm were mapped in the understory of a 3.16 ha Eucalyptus spp. and Corymbia spp. plantation, located in the municipality of Lavras, SE Brazil. The largest nearby mature tree of X. brasiliensis was considered as the propagules source. Linear regressions were used to assess the influence of the distance of propagules source on the population parameters (density, basal area and height). The spatial pattern of trees was assessed through the Ripley K function. The overall pattern showed that the propagules source distance had strong influence over spatial distribution of trees, mainly the small ones, indicating that the closer the distance fro...
Clear understanding of the links between ecological functions and biodiversity is needed to asses... more Clear understanding of the links between ecological functions and biodiversity is needed to assess and predict the true environmental consequences of human activities. Several key ecosystem functions are provided by coprophagous beetles in the subfamily Scarabaeinae (Coleoptera: Scarabaeidae), which feed on animal excreta as both adults and larvae. Through manipulating feces during the feeding process, dung beetles instigate a series of ecosystem functions ranging from secondary seed dispersal to nutrient cycling and parasite suppression. Many of these ecological functions provide valuable ecosystem services such as biological pest control and soil fertilization. Here we summarize the contributions of dung beetles to nutrient cycling, bioturbation, plant growth enhancement, secondary seed dispersal and parasite control, as well as highlight their more limited role in pollination and trophic regulation. We discuss where these ecosystem functions clearly translate into ecosystem services, outline areas in critical need of additional research and describe a research agenda to fill those gaps. Due to the high sensitivity of dung beetles to habitat modification and changing dung resources, many of these ecological processes have already been disrupted or may be affected in the future. Prediction of the functional consequences of dung beetle decline demands functional studies conducted with naturally assembled beetle communities, which broaden the geographic scope of existing work, assess the spatio-temporal distribution of multiple functions, and link these ecosystem processes more clearly to ecosystem services.
Experimental studies linking community composition to functioning are typically confined to small... more Experimental studies linking community composition to functioning are typically confined to small and closed micro- or mesocosms. Such restricted conditions may affect both species’ biology and their environment. Yet, targeting simple features in the behaviour of species may circumvent these constraints. Focusing on ecological functions provided by dung beetles, we test whether large, open-top cages – MESOCLOSURES – will intercept the flight trajectories of beetles, thereby allowing manipulation of local community composition.MESOCLOSURES were built in both tropical forest (Brazil) and temperate grasslands (Finland), thus testing their general efficiency. Within the respective environments, we varied different aspects of MESOCLOSURE design: in the tropical forest, we examined the impact of MESOCLOSURE dimensions on exclusion efficiency, whereas in the temperate grassland, we assessed the potential for selectively excluding and including community members by different mesh sizes. In the temperate environment, we also went from method to application, using MESOCLOSURES to relate community composition to functioning under two simulated grazing regimes.MESOCLOSURES allowed efficient manipulation of dung beetle communities, maintaining dung beetle densities at intended levels in both temperate and tropical systems. In the tropics, the smallest cages (1 × 1 m) offered the highest contrast in beetle densities inside vs. outside of the fence, whereas the largest cages (9 × 9 m) offered the lowest. Nonetheless, densities inside cages never exceed one-fifth of those outside. At the temperate site, manipulations of community structure through mesh size yielded significant differences in functioning and suggested an interaction between small dung-dwelling species and large tunnelling species. Within cages, higher grazing was reflected in augmented dung removal.We conclude that MESOCLOSURES can be effectively used to study dung beetle functions across habitats and latitudes. As applied insights, the present study adds resolution to the significance of different functional groups of dung beetles and shows that grazing pressure may have an important impact on the ecosystem functions that they provide. Overall, this study suggests that targeted manipulation of dispersal may offer new solutions for linking fauna to ecosystem functions with minimal impact on the processes measured.
Brazilian journal of biology = Revista brasleira de biologia, 2010
The objectives of this study were to evaluate the influence of propagules source and the implicat... more The objectives of this study were to evaluate the influence of propagules source and the implication of tree size class on the spatial pattern of Xylopia brasiliensis Spreng. individuals growing under the canopy of an experimental plantation of eucalyptus. To this end, all individuals of Xylopia brasiliensis with diameter at soil height (dsh) > 1 cm were mapped in the understory of a 3.16 ha Eucalyptus spp. and Corymbia spp. plantation, located in the municipality of Lavras, SE Brazil. The largest nearby mature tree of X. brasiliensis was considered as the propagules source. Linear regressions were used to assess the influence of the distance of propagules source on the population parameters (density, basal area and height). The spatial pattern of trees was assessed through the Ripley K function. The overall pattern showed that the propagules source distance had strong influence over spatial distribution of trees, mainly the small ones, indicating that the closer the distance fro...
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Papers by Julio Louzada